Field of the Invention
This disclosure relates to a liquid discharge head and a method of manufacturing the same.
Description of the Related Art
Examples of a liquid discharge head to be used in a liquid discharge apparatus such as an inkjet printer include a configuration including a print element board, a supporting member configured to support the print element board, an electric wiring board, and a wiring portion. The print element board includes discharge ports configured to discharge liquid, and an energy generating element configured to generate discharge energy for discharging the liquid. The electric wiring board is interposed between the print element board and the wiring portion, and configured to transmit an electric signal supplied to the wiring portion to the print element board.
A liquid discharge head disclosed in Japanese Patent Laid-Open No. 10-230602 is provided with connecting terminals (connecting pads) and positioning terminals respectively on the wiring portion and the electric wiring board. The wiring portion and the electric wiring board are arranged at positions where the connecting terminals overlap each other and are connected to each other by aligning positioning terminals on both of the boards respectively. Accordingly, the connecting terminals are electrically connected to each other and are mechanically fixed.
In liquid discharge heads of recent years, the number of energy generating elements mounted on the print element board is increased in order to improve a recording speed. In keeping with this trend, the number of wires for transmitting and receiving an electric signal to be supplied to the energy generating element and the number of connecting terminals also increase. Consequently, an increase in size of the electric wiring board, more specifically, an increase in width is required.
The electric wiring board and the wiring portion are often connected by thermocompression bonding. Normally, a base material of the electric wiring board and a base material of the wiring portion are different, and a magnitude of thermal expansion is different between the electric wiring board and the wiring portion at the time of connection (at the time of thermocompression bonding) depending on the difference coefficient of linear expansion between these base materials. In other words, since an amount of expansion (an amount of elongation) of the electric wiring board and an amount of expansion (amount of elongation) of the wiring portion are different at the time of connection, the relative position therebetween is misaligned. Since the size of the member is proportional to an amount of elongation, the wider the width of the connecting portion, the larger the elongation in a width direction it has, and a significant misalignment of the relative position may result. Consequently, connection failure due to insufficient contact between the connecting terminals and short circuit due to accidental connection between the connecting terminals which should not contact with each other may occur.